Curtain Fabric Calculator.
Work out how many fabric widths and how much total fabric to buy for a single curtain or pair. Use your track width, finished drop, fabric width and chosen fullness.
Curtain measurements
Calculate fabric length from your actual pole, drop, fabric width and chosen fullness.
Use the fullness specified for your heading style or your own preference.
Pattern repeat & sewing allowance
Add only the allowance required by your chosen heading and hem construction.
Leave blank for plain fabric or when pattern matching is not required.
Fabric required
Enter your curtain and fabric measurements to calculate metres and yards.
How much curtain fabric do I need?
Curtain fabric depends on both the width you need to cover and the fullness of the finished curtain. The calculator multiplies the track or pole width by your chosen fullness, then divides that required finished width by the fabric width and rounds up to whole drops.
For a pair of curtains, an odd number of drops is rounded up so each curtain can use the same number of fabric widths. The result shows the drops required, cut length per drop and total fabric in metres and yards.
Why curtain fullness changes the fabric amount
Fullness is the ratio between the flat fabric width and the width the curtain covers when hung. A higher fullness needs more fabric across the window, so it can increase the number of drops even when the finished curtain length stays the same.
Choose the fullness recommended for your heading style, tape or hardware, or use the fullness you have already decided on. The calculator does not assume that every curtain heading uses the same ratio.
Pattern repeat, hems and heading allowance
Add the total extra length you need for the heading and hem to the finished curtain drop. If the fabric has a vertical pattern repeat that must align, enter the repeat and each cut length is rounded up to a complete repeat.
Pattern matching can therefore increase the fabric requirement by a different amount for different fabrics. Plain fabric or fabric that does not need repeat matching can leave the pattern-repeat field blank.
Frequently asked questions
How do I calculate how much curtain fabric I need?
Enter the pole or track width, finished curtain drop, fabric width and chosen fullness. The calculator determines the whole fabric widths required and the total length in metres and yards.
What curtain fullness should I use?
Use the fullness specified for your heading style, curtain tape or hardware, or the fullness you have chosen for the look you want. This calculator offers common ratios but does not prescribe one.
Why does a pair of curtains sometimes need an extra fabric width?
A pair normally needs the same number of drops on each side. If the calculated total is odd, the tool rounds up to the next even number so the pair can be divided equally.
How does pattern repeat affect curtain fabric?
When a vertical repeat is entered, each cut length is rounded up to a full repeat so adjacent drops have enough length for pattern alignment.
What should I include in heading and hem allowance?
Enter the total extra length required by the construction method you plan to use. The amount depends on your heading, hem and sewing method, so it is not prefilled.
Does this calculator include curtain lining?
No. The result is for the main curtain fabric. Lining, interlining, returns and other separate materials should be calculated from their own widths and construction requirements.
Can I calculate a single curtain instead of a pair?
Yes. Choose Single curtain and the calculator will not force the number of fabric widths to be even.